如何在PostgreSQL中将int转换为字符串

Question

我有这个：COALESCE(amount ,0) as amount。 amount的数据类型为numeric。

我想要0而不是N/A。我怎样才能做到这一点？我遇到错误：

ERROR:  invalid input syntax for type numeric: "N/A"

Answer 1

使用类型转换：

coalesce(CAST(amount AS text), 'N/A')

Answer 2

您更适合以下代码：coalesce(cast(nullif(amount, 0) as text), 'N/A')

有关保存的其他信息：

case 
  when coalesce(cast(nullif(a.amount1, 0) as text), 'N/A') = 'N/A' then 'N/A' 
  when coalesce(cast(nullif(a.amount2, 0) as text), 'N/A') = 'N/A' then 'N/A'  
  else (coalesce(cast(nullif(a.amount1 - a.amount2, 0) as text), 'N/A')) 
end as savings